Vulcanization of rubber



Patented Nov. 9, 1943 K i r vunermzmownafnwsssa L Delaware N Drawing. Applicatio'ifMirch 'li,i912,

Serial No. 4333633 1610mm. fccr-zso lss') from a thia'zoleor a thiazoline andR1'is ah aiyl group. The 'thiazyl'group may wlie2 11151120thialzyl, "l0

az'yl, '6-chlor 5-nitro 2 benzothiazyl, 6-hydroxy- 2-benzothiazyl, 5-ni'tro 2-benz'othia zyl, 5-chlor- 2-benzothiazy1, 'tetrahydro -Z EBnZothiazyl, the

"alpha 'and beta -naphthothiazyls both substituted and unsubstituted, and -:other 'alkyl, aryl, nitro, amino, hydroxy-halo, alkoxy, etc.-derivative's of the-aryIene=2-thiazyl'=group. The t-hiazylzgroup may also be 2-thiazy1 or a substituted thiazyl groupsuch'a's4 methyl-2-thiazyl, 4-5-dimethyl- Z-thiazyl, 5-methyl-2-thiazyl, 5-phenyl-2-thiazyl, 5 benzyl-2-thiazyl, 4-methoxy-5-methy1-2-thiazyl, 5-(4-chlorphenyl) -2-thiazyl or 4-chlor-2- thiazyl and other thiazyls substituted in the 4-, or 5-, or 4- and 5-positions with an alkyl, alkoxy, thialkyl, aryl, aralkyl, chloro or nitro, etc. group. The mercaptothiazolyl group may be Z-thiazolyl- 4-methyl-2-thiazy1, 4-ethyl-2-thiazo1yl, 4-benzyl- 2-thiazoly1 and 5-ch1oro-2-thiazolyl, or other groups in which the 4- or 5-position or both may be substituted with a usual substituent.

The R1 of the formula is a part of the sulfonamide group. In spite of the fact that it is usual amide, toluene sulfonamide, etc. R1 is referred to herein as a radical. It may be phenyl, tolyl, alpha naphthyl, beta naphthyl, xenyl, etc. and may form groups such a benzene-l-chloro sulfonylamido, toluene-2-hydroxy-4-sulfonylamido, a naphthalene disulfonylamido, xylene sulfonylamido mixture or a mixture of any one or more Of the sulfonylamido compounds.

The new accelerators may be prepared in one of several ways. For example, they may be prepared by mixin the mercaptothiazole or mercaptothiazoline, formaldehyde, and the sulfonamide and subjecting them to reacting conditions. As an alternative method, the mercaptothiazole or mercaptothiazoline may be reacted with a methylol sulfonamide. As a third method of preparing the compounds the sulfonamide may be reacted with a 2-methylol mercaptothiazole or mercaptothiazoline.

Representative methods of "craters arei'giv'n' below.

rammed lilhe new compound may be prepared -in a "'soi'vefit'sifch "asalcohbLas"fblldwsfsiiite fsven tfitfis g'fam's (0.1 3161) "am-fiercest g zothiazole, "1T1 gratis "(011" 'ihdl'lfif :11 I lf'sulfonaiiiide ana'sis "grains "enemyin stag of "011 men --6f'3'T 'fcifihildhfliefiiefid dtojj300 cc. of alcdhol rand names for anew minutes. To the solution was then added 25 rhli'of coiicentrated-hydrochloricacid. Themixturewasthen refluxedfor two hours, then alldwed to stand at 'room--temperat'ure. 'S6oh3'y11ow leaflets began to "separate. After filtering, washing and drying thesecrystals'they'weretfoundto'm"eltat161 162 irrmmpra'z The niat'rial o'f Example 3:1 can also be made without theuse of an acidpatalyst. Thirty-three and four-tenths grams of 2-mercaptobenzothiazolejfi lbfig ramsl of ip-toluenei sulfonamide and 6.0 grams of parafor'maldehyde were added to 300 foo. ofibenZhe in "a 'flask diiipped'with'a stirrer, ther nmniet'efrand -r'eflux containing a water trap in the"cdndensate'return. When no more Water warrants, thefefiuxiii'g was stopped, and ilask and contents allowed to cool. Yellow leaflets melting at 161-162 C. separated out in a yield of 86%. The analysis for nitrogen, calculated at 8.00%; found, 7.67%. This indicates the reaction of equal mols of the three reactants and the formula is presumed to be that given above.

Example 3 Substituting 2-mercapto-6-ethoxy benzothiazole for 2-mercaptobenzothiazo1e in the procedure of Example 2, the reaction proceeds smoothly to give the corresponding derivative. In this experiment, one tenth molar quantities were used in a solution of cc. of toluene. The theoretical amount of water of condensation was obtained and the crystalline reaction product after recrystallizing from toluene, melted at 157 0.

Example 4 Alkyl or unsubstituted mercaptothiazoles undergo the reaction with formaldehyde and a suifonamide as readil as arylene mercaptothiazoles. Thirteen and one-tenth grams of 4-methyl-2- mercaptothiazole, 17.1 grams of p-toluene sulfonamide and 3.0 grams of paraformaldehyde were heated to the refluxing temperature of tolume 100 cc. of this solvent. The reaction proceeds smoothly and the crystalline reaction product melted at 134 C. and after recrystallization with a stirrer and a reflux witha water trap in the return. The suspension is heatedto refluxing of the solvent when five drops of concentrated hydrochloric acid is added.. Six,gra rns.. of-paraformaldehyde is added in portions-.and-refluxing is continued until no more water is obtained in the trap. In this case, 3.4 cc. of water was reco'vered The reaction product crystallizes out'on' cooling f and is obtained as white crystals. After crystallization from benzene, the product wasfound to meltat126-128 C. I I g r H Materials made accordingto Example 2', 3. and 4 were tested by compounding them in rubber according to the following formula:

The. resultsoflthese tests are given-in: the folw1n8 e=- l r v d Modulus Accelerator 'f 33 Tensile Elong Xylem. Per cent Examp1e2 20/240 110 900 13 i 37 30 142 830 20 66 178 e 805 27 96 '60 182. 755 35 133 ErampleEL 5' 11/240 73 9 1 Y .I 105 i 865 14 ".43 I 40.. .130 s25; 19 cs i V v I 151 765 28 v 103 Example 4.' ..'..,j. 20 240 105 8'90 1a 40 i The activity of this class of compounds when used for the acceleration of vulcanization is indicated by the above physical properties of the rubbers produced.

Theaccelerators are especially active when used with a small amount 01 a non-volatile or a slightly volatile organic base, such'as diphenylguanidine, di-o-tolyl guanidine, hexamethylene tetramine; methylene anilinemethylene di piperidine, dibenzylamine etc. The use 01 such a base is not essential.

I claim:

1. The process of vulcanizing rubber which comprises vulcanizing the rubber in the presence :of an accelerator having the formula "where R is a radical of the group consisting of thiazyls and thiazolyls and R1 is an aryl radical.

. 2.1'1he method of treating rubber which comprises vulcanizing the rubber in the presence of an N-,(2-benzothiazylthiomethylene) aryl'sulfonamide as an accelerator. 1

' 3. The process of vulcanizing rubber which comprisesvulcanizlng the rubber in the presence of an organic base and an accelerator having the formula R'S-CH:NHSO2R1, where R is a radical of the group consisting of thiazyls a -s-cnhmr -soa-a where R-is a radical of the group consisting 'of thiazylsand thiazolyls and R1 is an aryl radical;

6; Rubber vulcanized inthe presence of an N '(2-benzothiazylthiomethylene) arylsulfonaniide as an accelerator. 

